Thread safe fast integer

Question

So I have this class that holds 3 counters:

    public class Files
    {
        private static ObservableCollection<Files> _files = new ObservableCollection<Files>();
        private static int _inProcess;
        private static int _finished;
        private static int _inQueue;

        public static ObservableCollection<Files> List
        {
            get { return _files ; }
            set { _files = value; }
        }

        public static int InProcess
        {
            get { return _inProcess; }
            set
            {
                _inProcess = value;
            }
        }

        public static int Finished
        {
            get { return _finished; }
            set
            {
                _finished = value;
            }
        }

        public static int InQueue
        {
            get { return _inQueue; }
            set
            {
                _inQueue = value;
            }
        }
}

And from another class I want to add value to this fields:

Interlocked.Increment(ref Files.InProcess);

But got this error:

A property or indexer may not be passed as an out or ref parameter.

This works fine:

Files.InProcess++;

How can i fix it ?

@DannyNitman You *really* need to know what you're doing if you want to write lock free multithreaded programs. If you aren't *intimately* familiar with a lot of very complex rules around memory management in C# then you'll end up writing programs that don't work. — Servy, Jan 23 '18 at 17:50
"Properties are not variables. They are methods, and cannot be passed to ref parameters." : https://msdn.microsoft.com/en-us/library/14akc2c7(v=vs.120).aspx — PaulF, Jan 23 '18 at 17:50
@MongZhu I don't think it makes much since to protect a local variable. — juharr, Jan 23 '18 at 17:50

score 2 · Answer 1 · answered Jan 23 '18 at 17:48

2

The error is pretty straightforward. You can't pass a property as ref. In this case the best option is to create a method

public static void IncrementInProcess() { Interlocked.Increment(ref _inProcess); }

answered Jan 23 '18 at 17:48

Corentin Brossutti

29
1

I can put this inside my Files class where _inProcess is member of this class ? – Danny Nitman Jan 23 '18 at 17:52
@DannyNitman Yes. While I'm at it, your properties are pretty pointless since the get and set are both public and no check is done in either case. You should either a) not use them at all or b) use auto-implemented properties – Corentin Brossutti Jan 23 '18 at 17:58

Thread safe fast integer

1 Answers1